Losing control of the vegetation in your garden often brings on a feeling of hopelessness. Much less so, however, if the garden belonged to a previous owner and you have recently taken possession.

By this morning's post I have heard from a friend who is moving house. 'I never thought that destruction could be so much fun - pulling out kitchens, bathrooms etc. It is a little like the joy I discovered in the past few years to be had from removing trees and large shrubs from the garden. I don't remember ever feeling anything but relief and even pleasure from such removals.' But that is the attitude of the professional gardener, which my friend is. The pro can see what needs to be done and gets on with it, uncluttered by nerves or sentimentality. The amateur is far more tentative and hesitant. Yet too much clutter, too much shade, are the obvious faults that most need to be remedied in a countless number of gardens. Let there be space, let there be light, the cry goes up.

Some trees, such as self-sown sycamores that have become monsters simply through lack of early remedial action, are obvious examples. They must be the first to go. Decision on the fate of other trees may need debating. They may be old and gnarled and picturesque, and your inclination might understandably be to leave them to be dealt with by the next big storm. But that could be extremely messy, not to say dangerous. Calculated replacements have much to be said for them, so that you have (if the size of the garden allows it) a range of ages in the trees you own - young apples and pears as well as old, for instance.

Protection against road noise, ugly views and prying eyes are other considerations. But if you hope to remain where you are for years, as the majority of passionate gardeners will, then making a plan for continuous renewal becomes important.

Shrubs, especially evergreens, are a great defence in many ways, especially, in our exposed land, against wind. But those defenders often become boorish intruders in the course of time a gloomy bulk with a vast, unused interior that is unproductively taking up precious space. Could you not cut them back, more or less hard, perhaps very hard and almost to the ground, allowing them to sprout again from there? Often, the answer is yes. In fact, it could spell a new life for such as those tired, spent aucubas that have never been fed or pruned. But I would pause at this point - there are aucubas and aucubas, and, alas, those most often planted in the past are often the most boring available, the spotted aucubas weakly spotted so that the spots fail to contribute to any sort of personality. But there are exciting clones of aucuba - 'Crotonifolia' is one such - whose leaves are deliriously spotted and flaunt their spottiness with panache. Others have elegant, shiny leaves of svelte outline. Others, again, are female and will, given a nearby male partner, cover themselves with red berries during this 'dead' season, for their fruit ripens now, and with all the freshness that we normally expect of newly-ripened fruit in the autumn.

Many rhododendrons are greatly improved by a hard cut-back, and I am not thinking only of the ubiquitous Rhododendron ponticum, which is a great provider of shelter and handsome with its mauve blossom in June, but is otherwise a dull dog. Many rhododendron hybrids respond wonderfully to being cut hard back.

Some conifers, likewise, though not all. Yew and thuja, for example, come back from old wood, but not cypresses (including Leyland cypress) or junipers. I wrote a long chapter on the results of cutting back in my book, The Adventurous Gardener, and Stephen Anderton will be a lot more comprehensive in his forthcoming book, Rejuvenating A Garden. Old camellias, even though they may continue to flower well, can become quite ugly as large shrubs, with much old wood exposed. A hard cut-back in spring will result in a wealth of young shoots that won't flower next year but will, abundantly, the year after. (If you're greedy, you can even wait until after flowering and do the job in May.) I should, perhaps, add that some camellias, notably Camellia japonica cultivars, are normally shy-flowering in the north, where their wood receives insufficient ripening to make much flower bud - in which case, replace them with something more reliable.

Other shrubs that need a bit of extra warmth to perform well might include forsythia, weigela, choisya, Daphne odora and Cercis, the Judas tree.

These are sometimes treated as warm-wall shrubs in the north, thus providing them with extra, radiated heat.

If you regularly prune your forsythias, philadelphus, deutzias, lilacs, hydrangeas and roses, there will be an ongoing process of rejuvenation, this going hand-in-hand with feeding and mulching. The shrub will provide you with plenty of young growth that can be left to flower, while older, tired branches are regularly removed. But if these shrubs (and many more) have not been attended to over a period of years (which is often the situation you will have to face on moving into a new property), they will be occupying a great deal of unproductive space. The only rational method of rejuvenation in such circumstances will be to cut the whole shrub right down, possibly spreading this ruthless action over a couple of years, slaughtering one half of the shrub one year, and the other half the next.